Searching multilingual documents based on document structure extraction

ABSTRACT

An approach is provided for searching multilingual documents. A first classification is determined that includes a first document and other document(s) by minimizing a first distance between a first numerical fixed length vector for the first document and other numerical fixed length vector(s) for other document(s). Based on a query and a natural language detected in the query, a second document is selected. A second stream modeling the second document is encoded as a second numerical fixed length vector. Based on a distance between the first and second numerical fixed length vectors being less than a threshold, the first classification is identified as including the second document. Documents in the first classification are ranked and presented as having content matching the second document&#39;s content. At least one of the ranked documents is expressed in a natural language different from the natural language of the second document.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application claiming priority to Ser.No. 15/818,860 filed Nov. 21, 2017, now U.S. Pat. No. 10,691,734 issuedJun. 23, 2020, the contents of which are hereby incorporated byreference.

BACKGROUND

The present invention relates to information retrieval, and moreparticularly to retrieving multilingual documents.

International business and corporate globalization require thatcompanies communicate in many natural languages and dialects. For manyinstances of an event or an object, there are substantial amounts ofinterrelated reports, reviews, or descriptions from differentperspectives and in different natural languages. Multiple versions of asingle internal document of a company may be generated, where each ofthe versions has the same content, but is expressed in a differentnatural language. A user may utilize a search query expressed in anatural language in which the user is proficient in order to findmultilingual versions of a document. Known information retrieval systemstranslate multilingual versions of a document into a single naturallanguage, and then apply searches across the multilingual versions usingthat single natural language. The translation of a document is ofteninaccurate, especially if the document includes terminology in a domainof a specific industry. To improve translation accuracy, users mustexpend effort to understand the meaning of the document and know how totranslate the document from one language to a different language,including how to translate terminology that is specific to a particularindustry's domain.

Other known information retrieval systems require multiple searchengines to search for multilingual versions of a document, where asingle search query is translated into multiple natural languages andeach search engine searches for text in a corresponding one of thosenatural languages. The translation of the search query is subject to thesame inaccuracies and difficulties mentioned above.

Still other known information retrieval systems perform multilingualsearching based on identifying images in a first document expressed in afirst natural language and then searching for documents expressed inother natural languages that include images similar to the images in thefirst document. Different language versions of a document that have thesame textual content, however, may not always include similar images,and therefore inaccurate search results may be generated.

Accordingly, there is a need for a technique that efficiently searchesfor multilingual documents without requiring translation of thedocuments or the search query and without requiring multiple,language-specific search engines.

SUMMARY

In one embodiment, the present invention provides a method of searchingdocuments expressed in multiple natural languages. The method includes acomputer extracting components of structures of the documents expressedin the multiple natural languages. The method includes based on theextracted components of the structures of the documents, the computerclassifying the documents into classifications including respective,mutually exclusive sets of documents expressed in different respectivenatural languages. The documents in each set have matching content. Themethod further includes the computer detecting a natural language in aquery. The method further includes based on the query and the detectednatural language and based on a utilization of a search engine, thecomputer selecting a document included in the documents whose content isindicated by the query and whose natural language matches the detectednatural language. The method further includes the computer extractingfirst components of a structure of the selected document. The methodfurther includes based on the extracted first components, the computeridentifying a classification included in the classifications asincluding the selected document. The method further includes thecomputer identifying one or more other documents in the identifiedclassification. The method further includes the computer presenting theone or more other documents as having content that matches the contentof the selected document. The one or more other documents are expressedin one or more respective natural languages different from the naturallanguage of the selected document.

The aforementioned embodiment provides multilingual searching ofdocuments that is efficient and does not require translation or multiplelanguage-specific search engines. The aforementioned embodimentadvantageously allows a user who is proficient in only one language tocompose a search query to retrieve multilingual versions of a documentwithout requiring the user to translate the search query, the document,or any portion of the document, and without requiring the user tounderstand the semantic meaning of the document or to understanddomain-specific terminology used in the document.

The advantages discussed above also apply to the computer system andcomputer program product embodiments, which are summarized below.

In one optional aspect of the present invention, the steps of theaforementioned method are performed without translating the document,the one or more other documents, or the query. The aforementioned aspectof the present invention advantageously provides searching formultilingual documents where a user composes a search query to retrievemultilingual versions of a document without requiring the user to expendeffort in a difficult and error-prone exercise of understanding themeaning of any portion of the content of the multilingual versions ofthe document, and where the search does not require language-specificsearch engines to translate the search query or the document whoselanguage and content matches the search query.

In another optional aspect of the present invention, the step ofextracting the components includes modeling the structure of a firstdocument included in the documents as a first stream of the firstcomponents. The stream includes words of the document and otherindicators of the structure of the document, without an indication of asemantic meaning of the document. The step of extracting the componentsfurther includes replacing the words in the stream with a first tagindicating a word. The step of extracting the components furtherincludes subsequent to the step of replacing, encoding the stream as anumerical vector by utilizing a long short-term memory (LSTM) networkwhich learns the sequences of the components. The step of classifyingthe documents includes determining a classification that includes thedocument and the one or more other documents. The classification isdetermined by minimizing a distance between the numerical vector and oneor more other numerical vectors resulting from an encoding of one ormore other streams that model the one or more other documents. Theaforementioned aspect of the present invention advantageously provides alanguage-agnostic technique for determining multilingual documents thathave the same or similar content, without requiring translation orknowledge of semantic meaning of the content of the documents. Thedetermination of the same or similar multilingual documentsadvantageously utilizes an efficient comparison of densely encodedvectors which represent the structure of the documents rather than usinga comparison of extremely long vectors.

In another embodiment, the present invention provides a computer programproduct for searching documents expressed in multiple natural languages.The computer program product includes a computer readable storagemedium. Program instructions are stored on the computer readable storagemedium. The computer readable storage medium is not a transitory signalper se. The program instructions are executed by a central processingunit (CPU) of a computer system to cause the computer system to performa method. The method includes the computer system extracting componentsof structures of the documents expressed in the multiple naturallanguages. The method further includes based on the extracted componentsof the structures of the documents, the computer system classifying thedocuments into classifications including respective, mutually exclusivesets of documents expressed in different respective natural languages.The documents in each set have matching content. The method furtherincludes the computer system detecting a natural language in a query.The method further includes based on the query and the detected naturallanguage and based on a utilization of a search engine, the computersystem selecting a document included in the documents whose content isindicated by the query and whose natural language matches the detectednatural language. The method further includes the computer systemextracting first components of a structure of the selected document. Themethod further includes based on the extracted first components, thecomputer system identifying a classification included in theclassifications as including the selected document. The method furtherincludes the computer system identifying one or more other documents inthe identified classification. The method further includes the computersystem presenting the one or more other documents as having content thatmatches the content of the selected document. The one or more otherdocuments are expressed in one or more respective natural languagesdifferent from the natural language of the selected document.

In another embodiment, the present invention provides a computer systemincluding a central processing unit (CPU); a memory coupled to the CPU;and a computer readable storage device coupled to the CPU. The storagedevice includes instructions that are executed by the CPU via the memoryto implement a method of searching documents expressed in multiplenatural languages. The method includes a computer system extractingcomponents of structures of the documents expressed in the multiplenatural languages. The method further includes based on the extractedcomponents of the structures of the documents, the computer systemclassifying the documents into classifications including respective,mutually exclusive sets of documents expressed in different respectivenatural languages. The documents in each set have matching content. Themethod further includes the computer system detecting a natural languagein a query. The method further includes based on the query and thedetected natural language and based on a utilization of a search engine,the computer system selecting a document included in the documents whosecontent is indicated by the query and whose natural language matches thedetected natural language. The method further includes the computersystem extracting first components of a structure of the selecteddocument. The method further includes based on the extracted firstcomponents, the computer system identifying a classification included inthe classifications as including the selected document. The methodfurther includes the computer system identifying one or more otherdocuments in the identified classification. The method further includesthe computer system presenting the one or more other documents as havingcontent that matches the content of the selected document. The one ormore other documents are expressed in one or more respective naturallanguages different from the natural language of the selected document.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a system for searching documents expressedin multiple natural languages, in accordance with embodiments of thepresent invention.

FIG. 2 is a flowchart of a process of searching documents expressed inmultiple natural languages, where the process is implemented in thesystem of FIG. 1, in accordance with embodiments of the presentinvention.

FIG. 3 is an example of extracting features of structures of documentsand classifying the documents based on the extracted features within theprocess of FIG. 2, in accordance with embodiments of the presentinvention.

FIGS. 4A-4D depict an example of extracting and encoding features of astructure of a document within the process of FIG. 2, in accordance withembodiments of the present invention.

FIG. 5 is a block diagram of a computer that is included in the systemof FIG. 1 and that implements the process of FIG. 2, in accordance withembodiments of the present invention.

DETAILED DESCRIPTION

Overview

Embodiments of the present invention provide an efficient search ofmultilingual documents without translation. The multilingual documentsare documents whose contents are expressed in different respectivenatural languages. At least some of the documents have matching content,but are expressed in different natural languages (i.e., at least some ofthe documents are multilingual versions of the same document). Forexample, the same human resources policy manual of a corporation mayexist as a first document expressed in a first language, a seconddocument expressed in a second language, and a third document expressedin a third language, where the first, second, and third documents havematching content. The search of the multilingual documents describedherein is based on a first content of a first document matching a secondcontent of a second document if components (i.e., features) of thestructure of the first document match the components of the structure ofthe second document, even though the contents (i.e., text) of the firstand second documents may be expressed in different natural languages.The components of the structure of a document includes words, images,indicators of the start of lines, and labels that indicate, for example,space, tab, HyperText Markup Language (HTML) tag, title, subtitle,table, etc. Other components of the structure of a document may indicatethe position of an image, the length of a section, the number ofsentences, the number of paragraphs, the start of a sentence, and thestart of a paragraph. In one embodiment, the aforementioned documentsbeing searched are electronic structured documents that include embeddedmarkup coding that provides structural meanings to the whole documentand portions of the document. As used herein, versions of a document areinstances of a document that have content that is expressed inrespective languages that differ from one another, but the contentexpresses the same meaning in each of the versions.

As used herein, a natural language is defined as a language that hasevolved naturally in humans through use and repetition without consciousplanning or premeditation, and is different from constructed and formallanguages that include computer programming languages and languagesconsciously devised to study logic. As used herein, the term “language”and “languages” means a natural language and natural languages,respectively, unless the term is modified by a reference to aconstructed language and/or a formal language.

Known approaches to searching across one document and other documentsthat have the same content and are written in different languagesutilize translation of the other documents into the language of the onedocument, followed by a search across the one document and thetranslated documents. For example, a known approach may select anEnglish language human resources policy document and translate intoEnglish other human resource policy documents that are originallywritten in Chinese and Korean, and subsequently search across thedocuments using a query which is either in English originally, or istranslated into English if the query is originally in another language.The translations used in the known approach require effort and may beinaccurate translations, which may cause the search results to beinaccurate or incomplete. Other known approaches to searching across theabove-mentioned documents written in different languages involve theutilization of different search engines for each language, but stillintroduce inaccuracies of translation in translating a search query intothe different languages, which again may cause the search results to beinaccurate or incomplete. Furthermore, a user may need to translate orunderstand the meaning of the content of the search results, which areexpressed in different languages, in order to verify that the documentsin the search results actually have the same content, but the user maynot have the level of proficiency in the different languages to (i)perform the translation, (ii) understand the meaning of the documents indifferent languages, or (iii) understand the meaning of specializedterminology in the documents. Still other known approaches to searchingacross multilingual documents utilize image similarity recognition bysearching a first document by one language, determining images includedin the first document, and finding documents in other languages whichinclude images similar to the images in the first document. The imagesimilarity recognition approach may cause inaccurate search resultsbecause documents in different language versions may not always includesimilar images. Embodiments of the present invention overcome theaforementioned deficiencies of the known approaches of searchingmultilingual documents by using extracted features of documentstructure, under the assumption that multilingual versions of a documentusually have the same features of document structure and have the samelabels such as images, table, title, subtitle, and number of paragraphs.By using the extracted features of document structure, embodiments ofthe present invention search for and retrieve multilingual versions of adocument without using translation and without requiring a user to havethe multiple language proficiency to understand the meaning of thecontent or the meaning of special terminology in different languages inthe multilingual versions of the document, thereby advantageouslyavoiding (i) an additional effort of translation of document contentinto a different language, (ii) a requirement of user proficiency inmultiple languages, and (iii) a requirement of user proficiency inindustry-specific terminology in multiple languages.

For example, a user utilizing a search of multilingual documents usingthe extracted document structure features, as disclosed herein,retrieves documents that consist of a company's product informationmanual, where the retrieved documents are in different languages butconsist of the same content (i.e., content that expresses the samemeaning). In this example, the user writes a search query in English andretrieves the product information manual in English because the user haslanguage proficiency in English, but the user also distributes the sameproduct information manual to first and second customers as a firstretrieved document written in Chinese and a second retrieved documentwritten in Korean, respectively, because the first and second customershave language proficiency in Chinese and Korean, respectively. In thisexample, the distribution of the document in different languages iscompleted without requiring the user to translate English into Chineseor Korean, and without requiring the user to have enough languageproficiency in Chinese and Korean to understand the meaning of thecontent of the first and second documents, or to understand the meaningof industry-specific terminology in the first and second documents.

System for Searching Multilingual Documents

FIG. 1 is a block diagram of a system 100 for searching documentsexpressed in multiple natural languages, in accordance with embodimentsof the present invention. System 100 includes a computer 102, whichexecutes a software-based multilingual search system 104, which includesthe following software-based components: a structure extraction tool106, a classifier engine 108, a language detection tool 110, a searchengine 112, an extractor/collector component 113, and a ranking engine114.

Structure extraction tool 106 receives document 116-1, . . . , document116-N, where N is an integer greater than one. Structure extraction tool106 extracts features of the structure of each of documents 116-1, . . ., 116-N.

Classifier engine 108 classifies documents 116-1, . . . , 116-N intomutually exclusive classifications generated by classifier engine 108,so that documents that have matching extracted features are included inthe same classification. Having extracted document structure featuresthat match is an indication that the documents have the same or similarcontent. At least one of the classifications includes documents thathave the same content but are expressed in different languages.

Language detection tool 110 receives a query 118, which is a searchquery to search for a document included in document 116-1, . . . ,document 116-N based on keyword(s). Language detection tool 110 detectsthe language in which query 118 is expressed. Language detection 1101110 sends query 118 to search engine 112, which is a search engine thatsearches across documents in the detected language of query 118. Searchengine 112 generates a search result that includes one or more documentsin the detected language of query 118. Extractor/collector component 113extracts the features of the structure of each of the documents in thesearch result and identifies the classification(s) generated byclassifier engine 108 that includes each of the documents in theaforementioned search result. Extractor/collector component 113retrieves the multilingual documents that are included in the identifiedclassification(s).

Ranking engine 114 ranks the documents in the search result and theretrieved multilingual documents, and presents the ranked documents asranked search results 120 in response to query 118.

In one embodiment, ranking engine 114 includes a software-based adjustor122 which extracts data about multiple factors, including current querylanguage, user language, and the popularity of documents in the searchresult. Adjustor 122 generates ranked search results 120 by ranking thedocuments based on the extracted data about the multiple factors.Adjustor 122 also collects user feedback about search results generatedby search engine 112 and adjusts ranked search results 120 according tothe collected user feedback. In an alternate embodiment, ranking engine114 ranks the documents according to one or more of the aforementionedmultiple factors, but does not include adjustor 122.

The functionality of the components shown in FIG. 1 is described in moredetail in the discussion of FIG. 2, FIG. 3, FIGS. 4A-4D, and FIG. 5presented below.

Process for Searching Multilingual Searching

FIG. 2 is a flowchart of a process of searching documents expressed inmultiple natural languages, where the process is implemented in thesystem of FIG. 1, in accordance with embodiments of the presentinvention. The process of FIG. 2 begins at step 200. Prior to step 202,multilingual search system 104 (see FIG. 1) receives documents 116-1, .. . , 116-N (see FIG. 1). In step 202, structure extraction tool 106(see FIG. 1) extracts components (i.e., features) of structures ofdocuments 116-1, . . . , 116-N (see FIG. 1).

In step 204, based on the components extracted in step 202, classifierengine 108 (see FIG. 1) generates classifications of documents 116-1, .. . , 116-N (see FIG. 1) so that documents that have matching extractedfeatures are grouped into the same classification. Documents having thesame classification is an indication that the documents have matchingcontent. At least one of the classifications includes documents thathave matching content and are expressed in different languages.

Subsequent to the classifications being generated in step 204 and priorto step 206, multilingual search system 104 (see FIG. 1) receives query118 (see FIG. 1), which is a search query to search across documents116-1, . . . , 116-N (see FIG. 1). In step 206, language detection tool110 (see FIG. 1) detects a language used in query 118 (see FIG. 1).

In step 208, based on query 118 (see FIG. 1) and the language detectedin step 206, search engine 112 (see FIG. 1) selects a document includedin documents 116-1, . . . , 116-N (see FIG. 1), so that the content ofthe selected document is indicated by query 118 (see FIG. 1) and thelanguage in which the selected document is expressed matches thelanguage detected in step 206.

In step 210, extractor/collector component 113 (see FIG. 1) extractsfirst components of a structure of the document selected in step 208.

In step 212, based on the first components extracted in step 210,extractor/collector component 113 (see FIG. 1) identifies aclassification included in the classifications generated in step 204that includes a document whose components of its structure match thefirst components extracted in step 210.

In step 214, extractor/collector component 113 (see FIG. 1) retrievesthe documents in the classification identified in step 212, where theretrieved documents include (1) the document selected in step 208 and(2) other document(s) (i) whose content matches the content of thedocument selected in step 208 and (ii) are expressed in respectivelanguage(s) that are different from the language detected in step 206.

In step 216, ranking engine 114 (see FIG. 1) rank the documentsretrieved in step 214 and presents the ranked documents as documentshaving matching content and are expressed in different languages. In oneembodiment, the ranking of the retrieved documents is based on a vectorof multiple factors, which include the current language of query 118(see FIG. 1), the language of the user who provided query 118 (see FIG.1), and the popularity of each of the retrieved documents. In oneembodiment, adjustor 122 collects user feedback about the search resultsprovided by search engine 112 (see FIG. 1) and adjusts the ranking ofthe retrieved documents based on the collected user feedback.

In one embodiment, the extraction of components of the structure of agiven document in step 202 and step 210 includes (1) modeling thestructure of the document as a stream of components, where the streamincludes words in the text of the document and further includes otherindicators of the structure of the document, without an indication ofthe semantic meaning of the document; (2) replacing the words in thestream with a tag that indicates a word (e.g., replace the words“travel,” “reimbursement,” and “policy” with “word,” “word,” and“word”); and (3) subsequent to replacing the words, encoding the streamas a numerical vector by utilizing a long short-term memory (LSTM)network 434 in a deep neural network architecture.

In one embodiment, the generation of the classifications in step 204includes determining a classification that includes a given document andone or more other documents by determining that distances are minimizedbetween a numerical vector that encodes the structure stream that modelsthe given document and each of one or more other numerical vectors thatencode one or more other structure streams that model the one or moreother documents (i.e., the distances are less than a predefinedthreshold distance). The identification of the classification in step212 includes (1) by utilizing an LSTM network, determining anothernumerical vector that encodes a structure stream that models anotherdocument; (2) determining a distance between the other numerical vectorand a numerical vector that encodes a structure stream that models afirst document that is included in the classification; (3) determiningthat the distance is less than a predetermined threshold distance; and(4) based on the distance being less than the threshold distance,determining that the one or more documents included in theclassification have content that matches the content of the otherdocument.

Examples

FIG. 3 is an example 300 of extracting features of structures ofdocuments and classifying the documents based on the extracted featureswithin the process of FIG. 2, in accordance with embodiments of thepresent invention. Example 300 includes structure extraction tool 106(see FIG. 1) receiving document 302, document 304, and document 306, andextracting (1) components 308 of the structure of document 302, (2)components 310 of the structure of document 304, and (3) components 312of the structure of document 306. The extraction of the aforementionedcomponents is included in step 202 (see FIG. 2). Classifier engine 108receives components 308, 310, and 312 and determines that components 310match components 312 and further determines that components 308 do notmatch components 310 or components 312. Based on components 308 notmatching components 310 or components 312, classifier engine 108generates a classification 314 that includes only document 302. Based oncomponents 310 matching components 312, classifier engine 108 generatesa classification 316 that includes document 304 and document 306. Thegeneration of classification 314 and classification 316 is included instep 204 (see FIG. 2).

FIGS. 4A-4D depict an example of extracting and encoding features of astructure of a document within the process of FIG. 2, in accordance withembodiments of the present invention. FIG. 4A depicts a first portion400 of the example of extracting and encoding document structurefeatures. First exemplary portion 400 includes a policy document 402. Instep 202 (see FIG. 2), structure extraction tool 106 (see FIG. 1)extracts components (i.e., features) of the structure of policy document402 and creates a structure stream 404 consisting of the aforementionedcomponents that were extracted from policy document 402. The structurestream 404 includes words in the textual content of policy document 402,indicators of a start of a new line, an indicator of an underscore, anindicator of a table, and labels for a list.

FIG. 4B depicts a second portion 410 of the example of extracting andencoding document structure features. Second exemplary portion 410includes structure stream 404. Multilingual search system 104 (seeFIG. 1) generates a simplified structure stream 412 by replacing all thewords included in structure stream 404 with the tag “word.”

FIG. 4C depicts a third portion 430 of the aforementioned example ofextracting and encoding document structure features. Policy document 402is a document called Policy XYZ Document which is written in English.Policy document 432 is also the Policy XYZ Document, but is written inChinese. Policy document 402 is encoded into simplified structure stream412 (see FIG. 4B) and policy document 432 is encoded into a similarsimplified structure stream (not shown in FIG. 4C). Multilingual searchsystem 104 (see FIG. 1) further encodes the aforementioned simplifiedstructure streams by employing a long short-term memory (LSTM) network434 in a deep neural network architecture, which continuously acceptsnew input and feedback from previous output to itself to memorize themeaningful part of a whole stream. Utilizing the LSTM network 434transforms simplified structure stream 412 (see FIG. 4B) into a firstencoded structure vector 436 and transforms the simplified structurestream that encodes policy document 432 into a second encoded structurevector 438. First encoded structure vector 436 and second encodedstructure vector 438 are numeric, fixed length vectors. Classifierengine 108 (see FIG. 1) applies a sigmoid function 440 to first andsecond encoded structure vectors 436 and 438 and determines whethersigmoid function 440 is minimized. If the sigmoid function 440 isminimized, classifier engine 108 determines that the policy documents402 and 432 have content that is the same or similar, and groups thedocuments in the same classification.

FIG. 4D depicts a fourth portion 450 of the aforementioned example ofextracting and encoding document structure features. After classifierengine 108 (see FIG. 1) uses the LSTM network 434 (see FIG. 4C) in atraining mode across documents to determine classifications of documentsthat have the same or similar content, a document stream encoder 452 inmultilingual search system 104 (see FIG. 1) encodes policy document 402into simplified structure stream 454. Subsequently, a document structureencoder 456 (i.e., document structure LSTM encoder) in multilingualsearch system 104 transforms simplified structure stream 454 into anencoded structure vector 458. In step 212, multilingual search system104 (see FIG. 1) identifies a classification as including a documentthat matches policy document 402 by determining that the document in theidentified classification is encoded by document structure encoder 456as an encoded structure vector that matches encoded structure vector458.

By generating encoded structure vectors which are numeric, fixed lengthvectors, multilingual search system 104 (see FIG. 1) advantageouslyrepresents documents in relatively short vectors rather than relativelylong vectors representing the simplified structure streams and avoidsdifficulties of comparing extremely long vectors to determine documentsthat have the same or similar content based on the documents having thesame structure. For example, a simplified structure stream may have avariable length of more than 3000, whereas the corresponding encodedstructure vector generated by document structure encoder 456 may have afixed length of only 100 elements.

Computer System

FIG. 5 is a block diagram of a computer 102 that is included in thesystem of FIG. 1 and that implements the process of FIG. 2, inaccordance with embodiments of the present invention. Computer 102 is acomputer system that generally includes a central processing unit (CPU)502, a memory 504, an input/output (I/O) interface 506, and a bus 508.Further, computer 102 is coupled to I/O devices 510 and a computer datastorage unit 512. CPU 502 performs computation and control functions ofcomputer 102, including executing instructions included in program code514 for multilingual search system 104 (see FIG. 1) to perform a methodof searching multilingual documents, where the instructions are executedby CPU 502 via memory 504. CPU 502 may include a single processing unit,or be distributed across one or more processing units in one or morelocations (e.g., on a client and server).

Memory 504 includes a known computer readable storage medium, which isdescribed below. In one embodiment, cache memory elements of memory 504provide temporary storage of at least some program code (e.g., programcode 514) in order to reduce the number of times code must be retrievedfrom bulk storage while instructions of the program code are executed.Moreover, similar to CPU 502, memory 504 may reside at a single physicallocation, including one or more types of data storage, or be distributedacross a plurality of physical systems in various forms. Further, memory504 can include data distributed across, for example, a local areanetwork (LAN) or a wide area network (WAN).

I/O interface 506 includes any system for exchanging information to orfrom an external source. I/O devices 510 include any known type ofexternal device, including a display, keyboard, etc. Bus 508 provides acommunication link between each of the components in computer 102, andmay include any type of transmission link, including electrical,optical, wireless, etc.

I/O interface 506 also allows computer 102 to store information (e.g.,data or program instructions such as program code 514) on and retrievethe information from computer data storage unit 512 or another computerdata storage unit (not shown). Computer data storage unit 512 includes aknown computer readable storage medium, which is described below. In oneembodiment, computer data storage unit 512 is a non-volatile datastorage device, such as a magnetic disk drive (i.e., hard disk drive) oran optical disc drive (e.g., a CD-ROM drive which receives a CD-ROMdisk).

Memory 504 and/or storage unit 512 may store computer program code 514that includes instructions that are executed by CPU 502 via memory 504to search multilingual documents. Although FIG. 5 depicts memory 504 asincluding program code, the present invention contemplates embodimentsin which memory 504 does not include all of code 514 simultaneously, butinstead at one time includes only a portion of code 514.

Further, memory 504 may include an operating system (not shown) and mayinclude other systems not shown in FIG. 5.

Storage unit 512 and/or one or more other computer data storage units(not shown) that are coupled to computer 102 may include documents116-1, . . . , 116-N (see FIG. 1), and simplified structured streams andencoded structure vectors that represent the structure of documents116-1, . . . , 116-N (see FIG. 1).

As will be appreciated by one skilled in the art, in a first embodiment,the present invention may be a method; in a second embodiment, thepresent invention may be a system; and in a third embodiment, thepresent invention may be a computer program product.

Any of the components of an embodiment of the present invention can bedeployed, managed, serviced, etc. by a service provider that offers todeploy or integrate computing infrastructure with respect to searchingmultilingual documents. Thus, an embodiment of the present inventiondiscloses a process for supporting computer infrastructure, where theprocess includes providing at least one support service for at least oneof integrating, hosting, maintaining and deploying computer readablecode (e.g., program code 514) in a computer system (e.g., computer 102)including one or more processors (e.g., CPU 502), wherein theprocessor(s) carry out instructions contained in the code causing thecomputer system to search multilingual documents. Another embodimentdiscloses a process for supporting computer infrastructure, where theprocess includes integrating computer readable program code into acomputer system including a processor. The step of integrating includesstoring the program code in a computer readable storage device of thecomputer system through use of the processor. The program code, uponbeing executed by the processor, implements a method of searchingmultilingual documents.

While it is understood that program code 514 for searching multilingualdocuments may be deployed by manually loading directly in client, serverand proxy computers (not shown) via loading a computer readable storagemedium (e.g., computer data storage unit 512), program code 514 may alsobe automatically or semi-automatically deployed into computer 102 bysending program code 514 to a central server or a group of centralservers. Program code 514 is then downloaded into client computers(e.g., computer 102) that will execute program code 514. Alternatively,program code 514 is sent directly to the client computer via e-mail.Program code 514 is then either detached to a directory on the clientcomputer or loaded into a directory on the client computer by a buttonon the e-mail that executes a program that detaches program code 514into a directory. Another alternative is to send program code 514directly to a directory on the client computer hard drive. In a case inwhich there are proxy servers, the process selects the proxy servercode, determines on which computers to place the proxy servers' code,transmits the proxy server code, and then installs the proxy server codeon the proxy computer. Program code 514 is transmitted to the proxyserver and then it is stored on the proxy server.

Another embodiment of the invention provides a method that performs theprocess steps on a subscription, advertising and/or fee basis. That is,a service provider, such as a Solution Integrator, can offer to create,maintain, support, etc. a process of searching multilingual documents.In this case, the service provider can create, maintain, support, etc. acomputer infrastructure that performs the process steps for one or morecustomers. In return, the service provider can receive payment from thecustomer(s) under a subscription and/or fee agreement, and/or theservice provider can receive payment from the sale of advertisingcontent to one or more third parties.

The present invention may be a system, a method, and/or a computerprogram product at any possible technical detail level of integration.The computer program product may include a computer readable storagemedium (or media) (i.e., memory 504 and computer data storage unit 512)having computer readable program instructions 514 thereon for causing aprocessor (e.g., CPU 502) to carry out aspects of the present invention.

The computer readable storage medium can be a tangible device that canretain and store instructions (e.g., program code 514) for use by aninstruction execution device (e.g., computer 102). The computer readablestorage medium may be, for example, but is not limited to, an electronicstorage device, a magnetic storage device, an optical storage device, anelectromagnetic storage device, a semiconductor storage device, or anysuitable combination of the foregoing. A non-exhaustive list of morespecific examples of the computer readable storage medium includes thefollowing: a portable computer diskette, a hard disk, a random accessmemory (RAM), a read-only memory (ROM), an erasable programmableread-only memory (EPROM or Flash memory), a static random access memory(SRAM), a portable compact disc read-only memory (CD-ROM), a digitalversatile disk (DVD), a memory stick, a floppy disk, a mechanicallyencoded device such as punch-cards or raised structures in a groovehaving instructions recorded thereon, and any suitable combination ofthe foregoing. A computer readable storage medium, as used herein, isnot to be construed as being transitory signals per se, such as radiowaves or other freely propagating electromagnetic waves, electromagneticwaves propagating through a waveguide or other transmission media (e.g.,light pulses passing through a fiber-optic cable), or electrical signalstransmitted through a wire.

Computer readable program instructions (e.g., program code 514)described herein can be downloaded to respective computing/processingdevices (e.g., computer 102) from a computer readable storage medium orto an external computer or external storage device (e.g., computer datastorage unit 512) via a network (not shown), for example, the Internet,a local area network, a wide area network and/or a wireless network. Thenetwork may comprise copper transmission cables, optical transmissionfibers, wireless transmission, routers, firewalls, switches, gatewaycomputers and/or edge servers. A network adapter card (not shown) ornetwork interface (not shown) in each computing/processing devicereceives computer readable program instructions from the network andforwards the computer readable program instructions for storage in acomputer readable storage medium within the respectivecomputing/processing device.

Computer readable program instructions (e.g., program code 514) forcarrying out operations of the present invention may be assemblerinstructions, instruction-set-architecture (ISA) instructions, machineinstructions, machine dependent instructions, microcode, firmwareinstructions, state-setting data, configuration data for integratedcircuitry, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++, or the like, andprocedural programming languages, such as the “C” programming languageor similar programming languages. The computer readable programinstructions may execute entirely on the user's computer, partly on theuser's computer, as a stand-alone software package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer or server. In the latter scenario, the remote computer may beconnected to the user's computer through any type of network, includinga local area network (LAN) or a wide area network (WAN), or theconnection may be made to an external computer (for example, through theInternet using an Internet Service Provider). In some embodiments,electronic circuitry including, for example, programmable logiccircuitry, field-programmable gate arrays (FPGA), or programmable logicarrays (PLA) may execute the computer readable program instructions byutilizing state information of the computer readable programinstructions to personalize the electronic circuitry, in order toperform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations (e.g., FIG. 2) and/or block diagrams (e.g., FIG.1 and FIG. 5) of methods, apparatus (systems), and computer programproducts according to embodiments of the invention. It will beunderstood that each block of the flowchart illustrations and/or blockdiagrams, and combinations of blocks in the flowchart illustrationsand/or block diagrams, can be implemented by computer readable programinstructions (e.g., program code 514).

These computer readable program instructions may be provided to aprocessor (e.g., CPU 502) of a general purpose computer, special purposecomputer, or other programmable data processing apparatus (e.g.,computer 102) to produce a machine, such that the instructions, whichexecute via the processor of the computer or other programmable dataprocessing apparatus, create means for implementing the functions/actsspecified in the flowchart and/or block diagram block or blocks. Thesecomputer readable program instructions may also be stored in a computerreadable storage medium (e.g., computer data storage unit 512) that candirect a computer, a programmable data processing apparatus, and/orother devices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions (e.g., program code 514) mayalso be loaded onto a computer (e.g. computer 102), other programmabledata processing apparatus, or other device to cause a series ofoperational steps to be performed on the computer, other programmableapparatus or other device to produce a computer implemented process,such that the instructions which execute on the computer, otherprogrammable apparatus, or other device implement the functions/actsspecified in the flowchart and/or block diagram block or blocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the Figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

While embodiments of the present invention have been described hereinfor purposes of illustration, many modifications and changes will becomeapparent to those skilled in the art. Accordingly, the appended claimsare intended to encompass all such modifications and changes as fallwithin the true spirit and scope of this invention.

What is claimed is:
 1. A method of searching multiple documentsexpressed in multiple natural languages, the method comprising the stepsof: a computer determining a first classification that includes (i) afirst document included in the multiple documents expressed in themultiple natural languages and (ii) one or more other documents, thefirst classification being determined by minimizing a first distancebetween (i) a first numerical fixed length vector resulting from anencoding of a first stream that models the first document and (ii) oneor more other numerical fixed length vectors resulting from an encodingof one or more other streams that model the one or more other documents;the computer detecting a first natural language in a query; based on thequery and the detected first natural language and based on a utilizationof a search engine, the computer selecting a second document included inthe multiple documents whose content is indicated by the query and whosenatural language matches the detected first natural language; thecomputer extracting components of a structure of the second document,wherein the step of extracting the components includes the steps of:modeling a structure of the second document as a second stream of thecomponents, the second stream including words of the second document andindicators of the structure of the second document, without anindication of a semantic meaning of the second document; replacing, by adocument stream encoder, the words in the second stream with a firsttag; and encoding, by a document structure encoder, the second stream asa second numerical fixed length vector by utilizing a long short-termmemory (LSTM) network; the computer determining a second distancebetween the second numerical fixed length vector and the first numericalfixed length vector; the computer determining that the second distanceis less than a threshold distance; based on the extracted components andthe second distance being less than the threshold distance, the computeridentifying the first classification as including the second documentand determining that a plurality of documents in the identified firstclassification have content that matches the content of the seconddocument; the computer ranking the plurality of documents in theidentified first classification based on (i) the first natural languagein the query, (ii) a second natural language of a user who provides thequery, and (iii) a popularity of the plurality of documents in theidentified first classification; and the computer presenting the rankedplurality of documents in the identified first classification as havingcontent that matches the content of the second document, at least one ofthe ranked plurality of documents in the identified first classificationbeing expressed in a respective natural language different from thenatural language of the second document.
 2. The method of claim 1,wherein the steps of determining the first classification, detecting thefirst natural language, selecting the second document, extracting thecomponents, and presenting the ranked plurality of documents areperformed without translating the second document, the plurality ofdocuments in the identified first classification, or the query.
 3. Themethod of claim 1, further comprising the steps of: the computercollecting user feedback about results of other queries of the multipledocuments; and based on the collected user feedback, the computeradjusting a ranking of the ranked plurality of documents.
 4. The methodof claim 1, further comprising the step of extracting indicators ofwords, labels, images, titles, subtitles, paragraphs, tables, and startsof new lines in the multiple documents.
 5. The method of claim 1,further comprising the step of: providing at least one support servicefor at least one of creating, integrating, hosting, maintaining, anddeploying computer readable program code in the computer, the programcode being executed by a processor of the computer to implement thesteps of determining the first classification, detecting the firstnatural language, selecting the second document, extracting the secondcomponents, determining that the second distance is less than thethreshold distance, identifying the first classification, determiningthat the plurality of documents in the identified first classificationhave the content that matches the content of the second document,ranking the plurality of documents in the identified firstclassification, and presenting the ranked plurality of documents.
 6. Acomputer program product for searching multiple documents expressed inmultiple natural languages, the computer program product comprising acomputer readable storage medium having program instructions storedthereon, wherein the computer readable storage medium is not atransitory signal per se, and the program instructions are executed by acentral processing unit (CPU) of a computer system to cause the computersystem to perform a method comprising the steps of: the computer systemdetermining a first classification that includes (i) a first documentincluded in the multiple documents expressed in the multiple naturallanguages and (ii) one or more other documents, the first classificationbeing determined by minimizing a first distance between (i) a firstnumerical fixed length vector resulting from an encoding of a firststream that models the first document and (ii) one or more othernumerical fixed length vectors resulting from an encoding of one or moreother streams that model the one or more other documents; the computersystem detecting a first natural language in a query; based on the queryand the detected first natural language and based on a utilization of asearch engine, the computer system selecting a second document includedin the multiple documents whose content is indicated by the query andwhose natural language matches the detected first natural language; thecomputer system extracting components of a structure of the seconddocument, wherein the step extracting the components includes the stepsof: modeling a structure of the second document as a second stream ofthe components, the second stream including words of the second documentand indicators of the structure of the second document, without anindication of a semantic meaning of the second document; replacing, by adocument stream encoder, the words in the second stream with a firsttag; and encoding, by a document structure encoder, the second stream asa second numerical fixed length vector by utilizing a long short-termmemory (LSTM) network; the computer system determining a second distancebetween the second numerical fixed length vector and the first numericalfixed length vector; the computer system determining that the seconddistance is less than a threshold distance; based on the extractedcomponents and the second distance being less than the thresholddistance, the computer system identifying the first classification asincluding the second document and determining that a plurality ofdocuments in the identified first classification have content thatmatches the content of the second document; the computer system rankingthe plurality of documents in the identified first classification basedon (i) the first natural language in the query, (ii) a second naturallanguage of a user who provides the query, and (iii) a popularity of theplurality of documents in the identified first classification; and thecomputer system presenting the ranked plurality of documents in theidentified first classification as having content that matches thecontent of the second document, at least one of the ranked plurality ofdocuments in the identified first classification being expressed in arespective natural language different from the natural language of thesecond document.
 7. The computer program product of claim 6, wherein thesteps of determining the first classification, detecting the firstnatural language, selecting the second document, extracting thecomponents, and presenting the ranked plurality of documents in theidentified first classification are performed without translating thesecond document, the plurality of documents in the identified firstclassification, or the query.
 8. The computer program product of claim6, wherein the method further comprises the steps of: the computersystem collecting user feedback about results of other queries of themultiple documents; and based on the collected user feedback, thecomputer system adjusting a ranking of the ranked plurality ofdocuments.
 9. The computer program product of claim 6, wherein themethod further comprises the step of extracting indicators of words,labels, images, titles, subtitles, paragraphs, tables, and starts of newlines in the multiple documents.
 10. A computer system comprising: acentral processing unit (CPU); a memory coupled to the CPU; and acomputer readable storage device coupled to the CPU, the computerreadable storage device containing instructions that are executed by theCPU via the memory to implement a method of searching multiple documentsexpressed in multiple natural languages, the method comprising the stepsof: the computer system determining a first classification that includes(i) a first document included in the multiple documents expressed in themultiple natural languages and (ii) one or more other documents, thefirst classification being determined by minimizing a first distancebetween (i) a first numerical fixed length vector resulting from anencoding of a first stream that models the first document and (ii) oneor more other numerical fixed length vectors resulting from an encodingof one or more other streams that model the one or more other documents;the computer system detecting a first natural language in a query; basedon the query and the detected first natural language and based on autilization of a search engine, the computer system selecting a seconddocument included in the multiple documents whose content is indicatedby the query and whose natural language matches the detected firstnatural language; the computer system extracting components of astructure of the second document, wherein the step of extracting thecomponents includes the steps of: modeling a structure of the seconddocument as a second stream of the components, the second streamincluding words of the second document and indicators of the structureof the second document, without an indication of a semantic meaning ofthe second document; replacing, by a document stream encoder, the wordsin the second stream with a first tag; and encoding, by a documentstructure encoder, the second stream as a second numerical fixed lengthvector by utilizing a long short-term memory (LSTM) network; thecomputer system determining a second distance between the secondnumerical fixed length vector and the first numerical fixed lengthvector; the computer system determining that the second distance is lessthan a threshold distance; based on the extracted components and thesecond distance being less than the threshold distance, the computersystem identifying the first classification as including the seconddocument and determining that a plurality of documents in the identifiedfirst classification have content that matches the content of the seconddocument; the computer system ranking the plurality of documents in theidentified first classification based on (i) the first natural languagein the query, (ii) a second natural language of a user who provides thequery, and (iii) a popularity of the plurality of documents in theidentified first classification; and the computer system presenting theranked plurality of documents in the identified first classification ashaving content that matches the content of the second document, at leastone of the ranked plurality of documents in the identified firstclassification being expressed in a respective natural languagedifferent from the natural language of the second document.
 11. Thecomputer system of claim 10, wherein the steps of determining the firstclassification, detecting the first natural language, selecting thesecond document, extracting the second components, and presenting theranked plurality of documents are performed without translating thesecond document, the plurality of documents in the identified firstclassification, or the query.
 12. The computer system of claim 10,wherein the method further comprises the steps of: the computer systemcollecting user feedback about results of other queries of the multipledocuments; and based on the collected user feedback, the computer systemadjusting a ranking of the ranked plurality of documents.
 13. Thecomputer system of claim 10, wherein the method further comprises thestep of extracting indicators of words, labels, images, titles,subtitles, paragraphs, tables, and starts of new lines in the multipledocuments.